He is arguably China’s most jingoistic senior military voice, heralded by some as a national hero while hated by many more for his unvarnished battle cries for military actions when tensions soar between Beijing and its many adversaries and rivals, including Taiwan, Japan, the Philippines and most prominently, the United States.

Luo Yuan is also a quote machine for all stripes of writers and journalists. Universally considered a leading hawk in the tightly controlled information environment where senior officials speak in dialectical gobbledygook, Mr. Luo talks with clarity and unabashed chutzpah.

He wants to invade Taiwan as early as possible. He would readily resort to force in the territorial dispute with Japan over the Senkaku islands known in China as Diaoyudao. He supports a military alliance with Vladimir Putin’s Russia to challenge the United States in Asia and beyond. And he routinely belittles the nations of Southeast Asia, advocating military operations against countries such as the Philippines and Vietnam that have contested China’s expansive territorial and maritime claims in the South China Sea. Those inside China who disagree or challenge him are dismissed as “traitors” who should be punished without mercy. Some of his prominent critics have indeed been punished or jailed by the government.

China’s large numbers of nationalists endorse his fanatic views as a sign of the country’s renewed national virility, while his detractors cite his opinions as unmistakable demonstrations of China’s innate aggressiveness as a revisionist state bent on avenging its past humiliations, real and imagined. To those critics, Mr. Luo is a gift that keeps giving, the perfect tool to unmask China’s strategic ambiguity.

For the most part, however, Mr. Luo is seen as an authoritative source because his words align closely with what the country’s military is actually doing — as opposed to the official pronouncements of love for peace and stability. That only increases the demand for his hawkish but revealing views.

Bombastic and passionate about the need to be tough and macho toward the U.S. and China’s many neighbors, Mr. Luo stands out from a long list of hawks who permeate China’s print and electronic media by virtue of having the true “red blood.” He was born at the height of the Korean War into the family of a top communist military intelligence officer; even his given name of Yuan was taken from the official designation for China’s involvement in the Korean War.

When he was growing up, his father, Luo Qingchang, was Mao Zedong’s chief of international intelligence and espionage. During the Cultural Revolution, Mao turned his attacks on many of his lieutenants, including Mr. Luo’s father, though Luo Yuan himself was shielded by his father’s proteges within the People’s Liberation Army as a soldier serving in the remote southwest province of Yunnan.

After Mao’s death, Luo Yuan was able to return to his family in Beijing in 1978 and has been a renowned “princeling” ever since, eventually rising to the inner circle of PLA leadership. Until recently, Mr. Luo had been a major general, primarily serving as a theorist at the PLA’s Academy of Military Sciences and as an authorized spokesman for the Chinese military orthodoxy in state and social media.

Yet, it is in the social media where the outspoken Mr. Luo Yuan finally met his match — China’s ruthless Internet users known as Netizens. Despite being arrested by the tens of thousands, these Netizens, close to 600 million of them, keep criticizing the regime’s defenders, tearing Mr. Luo and his ilk apart mercilessly.

In February 2013, Maj. Gen. Luo Yuan received a special permission from the PLA high command to open his personal microblogging account in a popular portal called Weibo, in order to “take the commanding height of public opinion” in the nation.

To his complete surprise, he immediately faced an avalanche of derision and attacks by the Netizens.

In one of his initial postings on his Weibo account, Mr. Luo wrote that “we should fight in the battlefield, for the sake of our dear Motherland, our dear Communist Party, our dear PLA and our dear people!”

Commenters on the site exploded in ruthless rebuttals and counterattacks, some with passionate revulsion to his warmongering and hypocrisy, others with mock solemnity.

One long reply, which has since gone viral in China, took issue with Mr. Luo’s assumption that the government was still followed by the Chinese people without reservation. “When you use the word ‘we,’” the reply began, “you confuse ‘you’ with ‘we.’ ‘You’ are part of the 500 privileged Chinese families who are exploiting 1.3 billion Chinese people’s fortune; while ‘we’ are the exploited.”

“Take a look at Japan and Germany, their defeats in WWII marked the turning point toward their nations’ prosperity and their people’s happiness,” the counter posting continues. “Now take another look at the differences between North and South Korea, the mainland China and Taiwan — what the so-called victors [North Korea and China] want to sustain are reactionary institutions, evil, backwardness and dictatorship! … No, we are not going to fight your war!”

Mr. Luo has never fully recovered from the initial round of savage attacks, despite the arrests of many of his critics by the authorities.

Last week, Mr. Luo was again all over China’s state media, urging a swift military response to America’s “provocation” when the U.S. Navy’s destroyer USS Lassen sailed close by China’s man-made isle in the Spratly Islands chain to contest Chinese sovereignty claims in the South China Sea.

“Some of us believed the Americans would not come to us, but this time the wolf really has come to us!” he said on national TV, with relish, again urging China to immediately strike back with force.

• Miles Yu’s column appears Fridays. He can be reached at [email protected] and @Yu_miles.